EP1630183A1 - Polyurethane elastomers having improved antistatic behaviour - Google Patents

Abstract

Polyurethane elastomers (I), obtained by reaction of di- and/or polyisocyanate with at least a polyester polyol, optionally further polyetherpolyols and/or polyetheresterpolyols, optionally low-molecular chain lengthened and/or cross linked with OH numbers of 150-1870, in the presence of amine and/or metalloorganic catalysts, antistatic agents, optionally propellants and additives and/or auxiliary agents, are new. Polyurethane elastomers (I), obtained by reaction of di- and/or polyisocyanate with at least a polyester polyol (with OH numbers of 20-280 (preferably 28-150) and average functionalities of 1.5-3 (preferably 1.8-2.4)), optionally further polyether polyol (with OH numbers of 10-150 and functionalities of 1.5-8 (preferably 1.8-6)) and/or polyetherester polyol (with OH numbers of 20-280 and functionalities of 1.5-3 (preferably 1.8-2.4), optionally low-molecular chain length and/or cross linked with OH numbers of 150-1870, in the presence of amine and/or metalloorganic catalysts, antistatic agents consisting of (a) quaternary alkyl ammonium-monoalkyl sulfate of formula (R 1>R 2>R 3>R 4>N +>R 5>SO 4 -), (b) compounds (consisting of: (i) linear, OH group-free dicarboxylic acid esters of formula (COOR 6>-X-COOR 7>); and/or (ii) lactone group consisting of gamma -butyrolactone, gamma -valerolactone, alpha ,gamma -, beta ,gamma - and gamma gamma dimethylbutyrolactone), optionally propellants and additives and/or auxiliary agents, where the amount of (a) and (b) are 0.5-15 and 1.5-7.5 wt.%, respectively, are new. R 1>-R 4>1-20C alkyl, where the total amount of the carbon atoms of the four groups does not lie over 70; R 5>2-10C alkyl; X : 1-20C or a bond; and R 6>, R 7>1-20C alkyl.

Description

The invention relates to polyurethane elastomers (PUR elastomers) with improved antistatic charge behavior and to processes for their preparation and their use.

Semi-hard, elastic polyurethane molded parts in compact or cellular, i. slightly foamed design are based both on the basis of polyester-polyurethane compositions and polyether urethane compositions. To improve the electrostatic dissipation of these materials, antistatic additives are added to the polyetherurethane compositions.

A typical class of products of these additives are the known tetraalkyl ammonium alkyl sulphates (Polyurethane Handbook, Gunther Oertel, Carl Hanser Verlag, 2 ^nd edition 1993), both as concentrate and in solution, preferably in ethylene glycol or 1,4-butanediol, the PUR Reaction masses are added.

The alkylammonium sulfates are particularly suitable because they do not actively affect the polyurethane and typical side reactions such as polyurea and allophanate formation.

EP-A 1 336 639 discloses the use of quaternary ammonium compounds as internal antistatic agents for two-component polyurethanes. They are used in amounts of 0.5 to 3.0 wt .-%, based on the total weight of the polyurethane. In order to lower the melting range of the ammonium compounds, compounds lowering the melting point such as butyrolactone are added.

Disadvantage of these additives is that they must be added partly in high amounts of PUR mass to achieve low static values. Since they are present in the PUR matrix as a "filler", in addition, with increasing content in the PUR its elasticity and material strength is impaired.

It is an object of the present invention to improve the effect of tetraalkylammonium alkyl sulfates as an antistatic agent in the PUR foam, so that either the amount of this additive used can be reduced while the antistatic values remain the same or, if the amount used is the same, lower, i. better antistatic values are achieved.

Surprisingly, it has been found that the antistatic effect of the tetraalkylammonium alkyl sulfates can be markedly improved by the simultaneous addition of certain compounds. An increase of the electrostatic dissipation effect could be achieved twice or five times.

• a) Di- und/oder Polyisocyanaten mit
• b) mindestens einem Polyesterpolyol mit einer OH-Zahl von 20 bis 280, bevorzugt von 28 bis 150, und einer mittleren Funktionalität von 1,5 bis 3, bevorzugt von 1,8 bis 2,4,
• c) gegebenenfalls weiteren Polyetherpolyolen mit OH-Zahlen von 10 bis 150 und Funktionalitäten von 1,5 bis 8,0, vorzugsweise 1,8 bis 6,0 und/oder Polyetheresterpolyolen mit OH-Zahlen von 20 bis 280 und Funktionalitäten von 1,5 bis 3,0, bevorzugt 1,8 bis 2,4,
• d) gegebenenfalls niedermolekularen Kettenverlängerern und/oder Vernetzern mit OH-Zahlen von 150 bis 1870,
  in Gegenwart von
• e) Amin- und /oder metallorganischen Katalysatoren,
• f) Antistatika bestehend aus
  • f1) quartären Alkylammonium-monoalkylsulfaten der Formel (I)
    
             R¹R²R³R⁴ N⁺ R⁵SO₄-     (I)
    
    wobei R¹, R², R³ und R⁴ unabhängig voneinander C₁- bis C₂₀-Alkylreste sind, wobei die Gesamtanzahl der Kohlenstoffatome der vier Reste nicht über 70 liegt, und R⁵ ein C₂- bis C ₁₀-Alkylrest ist,
    und
  • f2) Verbindungen aus der Gruppe bestehend aus
    • i) linearen, OH-Gruppen-freien Dicarbonsäureestern der Formel (II)
      
      
      wobei X ein Rest mit 1 bis 20 Kohlenstoffatomen ist oder eine Bindung darstellt und R⁶ und R⁷ unabhängig voneinander C₁- bis C₂₀-Alkylreste sind,
    • ii) Lactonen aus der Gruppe bestehend aus γ-Butyrolacton, γ-Valerolacton, α,γ―, β,γ― und γγ- Dimethylbutyrolacton und
    • iii) Mischungen aus (i) und (ii),
• g) gegebenenfalls Treibmitteln und
• h) gegebenenfalls Zusatzstoffen und/oder Hilfsmitteln,

wobei die quartären Alkylammonium-alkylsulfate f1) in einer Menge von 0,5 bis 15 Gew.-%, bezogen auf das Polyurethanelastomer, vorliegen und die Verbindungen f2) in einer Menge von 1,5 bis 7,5 Gew.-%.The invention provides polyurethane elastomers obtainable by reaction of

• a) di- and / or polyisocyanates with
• b) at least one polyester polyol having an OH number of from 20 to 280, preferably from 28 to 150, and an average functionality of from 1.5 to 3, preferably from 1.8 to 2.4,
• c) optionally further polyether polyols having OH numbers of 10 to 150 and functionalities of 1.5 to 8.0, preferably 1.8 to 6.0 and / or Polyetheresterpolyolen having OH numbers of 20 to 280 and functionalities of 1.5 to 3.0, preferably 1.8 to 2.4,
• d) optionally low molecular weight chain extenders and / or crosslinkers having OH numbers from 150 to 1870,
  in the presence of
• e) amine and / or organometallic catalysts,
• f) Antistatic agents consisting of
  • f1) quaternary alkylammonium monoalkyl sulfates of the formula (I)
    
    R ¹ R ² R ³ R ⁴ N ⁺ R ⁵ SO ₄ - (I)
    
    wherein R ¹ , R ² , R ³ and R ^{4 are} independently C ₁ - to C ₂₀ -alkyl radicals, wherein the total number of carbon atoms of the four radicals is not more than 70, and R ^{5 is} a C ₂ - to C ₁₀ -alkyl radical .
    and
  • f2) compounds from the group consisting of
    • i) linear, OH group-free dicarboxylic esters of the formula (II)
      
      
      wherein X is a radical having 1 to 20 carbon atoms or is a bond and R ⁶ and R ^{7 are} independently C ₁ - to C ₂₀ -alkyl radicals,
    • ii) lactones selected from the group consisting of γ-butyrolactone, γ-valerolactone, α, γ-, β, γ- and γγ-dimethylbutyrolactone and
    • iii) mixtures of (i) and (ii),
• g) optionally propellants and
• h) optionally additives and / or auxiliaries,

wherein the quaternary alkyl ammonium alkyl sulfates f1) are present in an amount of 0.5 to 15 wt .-%, based on the polyurethane elastomer, and the compounds f2) in an amount of 1.5 to 7.5 wt .-%.

Another object of the invention are molded articles based on the polyurethane elastomers according to the invention.

Preferably, the PU elastomers are prepared by the prepolymer process, advantageously in the first step from at least a portion of the polyester polyol b) or its mixture with polyol component c) and at least one di- or polyisocyanate a) an isocyanate group-containing polyaddition adduct is prepared. In the second step, antistatic PUR elastomers can be prepared from such prepolymers containing isocyanate groups by reaction with the remaining part of the polyol component b) and / or optionally component c) and / or optionally low molecular weight chain extenders and / or crosslinkers d) and / or catalysts e) become. Component f) is preferably admixed with polyol b). Microcellular PU elastomers with a molding density of 200-1200 kg / m ³ can be prepared by adding propellant g) to the polyol b) in the second step.

Depending on the content of f), the molded parts produced from the PU elastomers according to the invention have antistatic properties in the range from 100 kOhm-1000 M ohms (measurement according to EN 344).

To prepare the PU elastomers according to the invention, the components are reacted in amounts such that the equivalence ratio of the NCO groups of the polyisocyanates a) to the sum of the isocyanate-reactive hydrogens of components b), c), d) and any chemically active Propellant 0.8: 1 to 1.2: 1, preferably 0.90: 1 to 1.15: 1 and in particular 0.95: 1 to 1.05: 1.

Suitable starting components a) for the process according to the invention are aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic polyisocyanates, as described, for example, by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75 to 136, for example those of the formula

Q (NCO) _n

in the n = 2-4, preferably 2, and Q is an aliphatic hydrocarbon radical having 2-18, preferably 6-10 C atoms, a cycloaliphatic hydrocarbon radical having 4-15, preferably 5-10 C atoms, an aromatic hydrocarbon radical having 6 -15, preferably 6-13 C atoms, or an aralipatic hydrocarbon radical having 8-15, preferably 8-13 G atoms, for example ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), 1, 12-Dodecandiisocyanat, cyclobutane-1,3-diisocyanate, cyclohexane-1,3- and -1,4-diisocyanate and any mixtures of these isomers, 1-isocyanato-3,3,5-tri-methyl-5-isocyanatomethyl-cyclohexane , 2,4- and 2,6-Hexahydrotoluylendiisocyanat and any mixtures of these isomers, hexahydro-1,3- and -1,4-phenylene diisocyanate, perhydro-2,4'- and -4,4'-diphenyl-methane diisocyanate, 1,3- and 1,4-phenylenediisocyanate, 1,4-durene diisocyanate (DDI), 4,4'-stilbenediisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate (TODI) 2,4- and 2,6-toluene ndiisocyanate (TDI) and any mixtures of these isomers, diphenylmethane-2,4'- and / or -4,4'-diisocyanate (MDI), or naphthylene-1,5-diisocyanate (NDI).

Further suitable examples are: triphenylmethane-4,4 ', 4 "-triisocyanate, polyphenyl-polymethylene-polyisocyanates, as obtained by aniline-formaldehyde condensation and subsequent phosgenation and, for example, in GB-PS 874 430 and GB-PS 848,671 p-isocyanatophenylsulfonyl isocyanates according to US Pat. No. 3,454,606, perchlorinated aryl polyisocyanates, as described in US Pat. No. 3,277,138, carbodiimide-containing polyisocyanates, as described in US Pat. No. 3,152,162 and in DE-A 25 04 400, 25 37 685 and 25 52 350, norbornane diisocyanates according to US-A 3 492 301, allophanate-containing polyisocyanates, as described in GB-PS 994 890, BE-PS 761 626 and NL-A 7 102 524 are polyisocyanates containing isocyanurate groups, as described in US-A 3,001,971, in DE-C 10 22 789, 12 22 067 and 1 027 394 and in DE-A 1 929 034 and 2 004 048, urethane-containing polyisocyanates, as described, for example, in Belgian Pat. No. 752,261 or in US Pat. No. 3,394 164 and 3,644,457, polyisocyanates containing urea groups according to DE-C 1 230 778, biuret-containing polyisocyanates, as described in US Pat. Nos. 3,124,605, 3,201,372 and 3,124,605 and British Patent No. 889,050 , Polyisocyanates prepared by telomerization reactions, as described in US Pat. No. 3,654,106, ester-containing polyisocyanates, as described in British Patent Nos. 965,474 and 1 072 956, in US Pat. No. 3,567,763 and in DE-C 12 31 688, reaction products of the abovementioned isocyanates with acetals according to DE-C 1 072 385 and polymeric fatty acid ester-containing polyisocyanates according to US Pat. No. 3,455,883.

It is also possible to use the isocyanate-group-containing distillation residues obtained in industrial isocyanate production, optionally dissolved in one or more of the abovementioned polyisocyanates. Furthermore, it is possible to use any mixtures of the aforementioned polyisocyanates.

Preferably used are the technically readily available polyisocyanates, e.g. the 2,4- and 2,6-toluene diisocyanate and any mixtures of these isomers ("TDI"), 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate and polyphenylpolymethylene polyisocyanates, as described by Prepared aniline-formaldehyde condensation and subsequent phosgenation, ("crude MDI") and carbodiimide groups, uretonimine groups, urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret polyisocyanates ("modified polyisocyanates"), in particular those modified polyisocyanates which differ from the 2, Derive 4- and / or 2,6-toluene diisocyanate or from 4,4'- and / or 2,4'-diphenylmethane diisocyanate. Also suitable are naphthylene-1,5-diisocyanate and mixtures of said polyisocyanates.

In the process according to the invention, however, particular preference is given to using prepolymers containing isocyanate groups which are prepared by reacting at least one partial amount of polyester polyol b) or at least one subset of a mixture of polyester polyol b), polyol component c) and / or chain extender and / or crosslinker d) with at least one aromatic diisocyanate from the group TDI, MDI, TODI, DIBDI, NDI, DDI, preferably with 4,4'-MDI and / or 2,4-TDI and / or 1,5-NDI to a urethane groups and isocyanate groups having polyaddition product with a NCO content of 10 to 27 wt .-%, preferably from 12 to 25 wt .-%.

As already stated, mixtures of b), c) and d) can be used to prepare the prepolymers containing isocyanate groups. However, according to a preferred embodiment, the prepolymers containing isocyanate groups are prepared without chain extenders or crosslinkers d).

The isocyanate group-containing prepolymers can be prepared in the presence of catalysts. However, it is also possible to prepare the isocyanate group-containing prepolymers in the absence of catalysts and to incorporate them into the reaction mixture only for the preparation of the PU elastomers.

Suitable polyester polyols b) can be prepared, for example, from organic dicarboxylic acids having 2 to 12 carbon atoms, preferably aliphatic dicarboxylic acids having 4 to 6 carbon atoms and polyhydric alcohols, preferably diols, having 2 to 12 carbon atoms, preferably 2 to 10 carbon atoms. Suitable dicarboxylic acids are, for example: succinic acid, malonic acid, glutaric acid adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid and terephthalic acid. The dicarboxylic acids can be used both individually and in admixture with each other. Instead of the free dicarboxylic acids, the corresponding dicarboxylic acid derivatives, e.g. Dicarboxylic acid mono- and / or diesters of alcohols having 1 to 4 carbon atoms or dicarboxylic anhydrides are used. Preferably used dicarboxylic acid mixtures of succinic, glutaric and adipic acid in proportions of, for example, 20 to 35/35 to 50/20 to 32 parts by weight, sebacic acid and especially adipic acid. Examples of dihydric and polyhydric alcohols are ethanediol, diethylene glycol, 1,2- and 1,3-propanediol, dipropylene glycol, methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol and 1,6-hexanediol , Neopentyl glycol, 1,10-decanediol, glycerol, trimethylolpropane and pentaerythritol. Preference is given to using 1,2-ethanediol, diethylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerol, trimethylolpropane or mixtures of at least two of the diols mentioned, in particular mixtures of ethanediol, 1,4-butanediol and 1,6-hexanediol. Hexanediol, glycerol and / or trimethylolpropane. It is also possible to use polyester polyols of lactones, e.g. ε-caprolactone or hydroxycarboxylic acids, eg. For example, o-hydroxycaproic acid and hydroxyacetic acid.

For the preparation of the polyester polyols, the organic, e.g. aromatic and preferably aliphatic polycarboxylic acids and / or derivatives and polyhydric alcohols catalyst-free or in the presence of esterification catalysts, conveniently in an atmosphere of inert gases, such as. Nitrogen, carbon monoxide, helium, argon, in solution and also in the melt at temperatures of 150 to 300 ° C, preferably 180 to 230 ° C optionally under reduced pressure to the desired acid number, advantageously less than 10, preferably less than 1 is polycondensed.

According to a preferred preparation process, the esterification mixture is polycondensed at the abovementioned temperatures to an acid number of 80 to 30, preferably 40 to 30, under atmospheric pressure and then under a pressure of less than 500 mbar, preferably 10 to 150 mbar. Suitable esterification catalysts are, for example, iron, cadmium, cobalt, lead, zinc, antimony, magnesium, titanium and tin catalysts in the form of metals, metal oxides or metal salts. However, the polycondensation can also be carried out in the liquid phase in the presence of diluents and / or entrainers, such as benzene, toluene, xylene or chlorobenzene, for the azeotropic distillation of the water of condensation.

For the preparation of the polyester polyols, the organic polycarboxylic acids and / or their derivatives are polycondensed with polyhydric alcohols advantageously in a molar ratio of 1: 1 to 1.8, preferably 1: 1.05 to 1.2. The polyesterpolyols obtained preferably have a functionality of 1.5 to 3, in particular 1.8 to 2.4 and a number average molecular weight of 300 to 8 400, preferably 400 to 6000, preferably 800 to 3500.

If appropriate, polyether polyols and / or polyether ester polyols c) are used to prepare the elastomers according to the invention. Polyether polyols can be prepared by known processes, for example by anionic polymerization of alkylene oxides in the presence of alkali metal hydroxides or alkali metal alkoxides as catalysts and with the addition of at least one starter molecule containing 2 to 3 reactive hydrogen atoms bound or by cationic polymerization of alkylene oxides in the presence of Lewis acids such as antimony pentachloride or borofluoride etherate. Suitable alkylene oxides contain 2 to 4 carbon atoms in the alkylene radical. Examples are tetrahydrofuran, 1,2-propylene oxide, 1,2- or 2,3-butylene oxide, ethylene oxide and / or 1,2-propylene oxide are preferably used. The alkylene oxides can be used individually, alternately in succession or as mixtures. Preference is given to using mixtures of 1,2-propylene oxide and ethylene oxide, the ethylene oxide being used in amounts of from 10 to 50% as endblock of ethylene oxide ("EO-cap"), so that the resulting polyols contain more than 70% primary OH end groups exhibit. Suitable starter molecules are water or dihydric and trihydric alcohols, such as ethylene glycol, 1,2-propanediol and 1,3-propanediol, diethylene glycol, dipropylene glycol, 1,4-ethanediol, glycerol, trimethylolpropane, etc. Suitable polyether polyols, preferably polyoxypropylene polyoxyethylene polyols have a functionality of 1.5 to 8 and preferred number average molecular weights of 500 to 8000, preferably 800 to 6000.

Other suitable polyether polyols are polymer-modified polyether polyols, preferably graft polyether polyols, in particular those based on styrene and / or acrylonitrile, which are obtained by in situ polymerization of acrylonitrile, styrene or preferably mixtures of styrene and acrylonitrile, e.g. in the weight ratio 90:10 to 10:90. preferably 70:30 to 30:70, are prepared in the aforementioned polyether polyols, and polyether polyol dispersions containing as disperse phase, usually in an amount of 1 to 50 wt .-%, preferably 2 to 25 wt .-%, eg inorganic fillers, polyureas, polyhydrazides, tertiary amino groups bound polyurethanes and / or melamine.

To improve the compatibility of b) and c), polyetherester polyols can also be used or added as c). These are obtained by propoxylation or ethoxylation of polyester polyols, preferably having a functionality of 1.5 to 3, in particular 1.8 to 2.4 and a number average preferred molecular weight of 400 to 6,000, preferably 800 to 3,500.

However, these polyether esters c) can also be obtained by esterification of ether polyols of the type described above, the ester components to be used corresponding to those described under b). These polyether esters preferably have a functionality of 1.5 to 3, in particular 1.8 to 2.4 and a number average preferred molecular weight of 400 to 6,000, preferably 800 to 3,500.

To prepare the PU elastomers according to the invention, it is additionally possible to use as component d) low molecular weight difunctional chain extenders, tri- or tetrafunctional crosslinkers or mixtures of chain extenders and crosslinkers.

Such chain extenders and crosslinkers d) are used to modify the mechanical properties, in particular the hardness of the PUR elastomers. Suitable chain extenders such as alkanediols, dialkylene glycols and polyalkylene polyols and crosslinking agents, for example 3- or 4-hydric alcohols and oligomeric polyalkylene polyols having a functionality of 3 to 4, usually have molecular weights <800, preferably from 18 to 400 and in particular from 60 to 300. Preferably used as chain extenders are alkanediols having 2 to 12, preferably 2, 4 or 6 carbon atoms, for example ethanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol and in particular 1,4-butanediol and dialkylene glycols having 4 to 8 carbon atoms, for example diethylene glycol and dipropylene glycol and polyoxyalkylene glycols. Also suitable are branched-chain and / or unsaturated alkanediols having usually not more than 12 carbon atoms, such as 1,2-propanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2-butyl 2-ethyl-1,3-propanediol, 2-butene-1,4-diol and 2-butyne-1,4-diol, diesters of terephthalic acid with glycols having 2 to 4 carbon atoms, such as terephthalic acid-bis-ethylene glycol or terephthalic acid bis-1,4-butanediol, hydroxyalkylene ethers of hydroquinone or resorcinol, for example 1,4-di (β-hydroxyethyl) hydroquinone or 1,3- (β-hydroxyethyl) -resorcinol, alkanolamines having 2 to 12 carbon atoms, such as ethanolamine, 2-aminopropanol and 3-amino-2,2-dimethylpropanol, N-alkyldialkanolamines, eg N-methyl- and N-ethyl-diethanolamine, (cyclo) aliphatic diamines having 2 to 15 carbon atoms, such as 1,2-ethylenediamine, 1, 3-propylenediamine, 1,4-butylenediamine and 1,6-hexamethylenediamine, isophoronediamine, 1,4-cyclohexamethylenediamine and 4,4'-diaminodicyclohexylmethane, N-alkyl, N, N'-dialkyl substituted u and aromatic diamines, which may also be substituted on the aromatic radical by alkyl groups, having 1 to 20, preferably 1 to 4 carbon atoms in the N-alkyl radical, such as N, N'-diethyl, N, N'-di-sec-pentyl N, N'-di-sec-hexyl, N, N'-di-sec-decyl and N, N'-dicyclohexyl, (p- or m-) -phenylenediamine, N, N 'Dimethyl, N, N'-diethyl, N, N'-diisopropyl, N, N'-di-sec-butyl, N, N'-dicyclohexyl, 4,4'-diamino-diphenylmethane, N, N'-di-sec-butylbenzidine, methylene-bis (4-amino 3-benzoic acid methyl ester), 2,4-chloro-4,4'-diamino-diphenylmethane, 2,4- and 2,6-toluenediamine.

The compounds of component d) can be used in the form of mixtures or individually. It is also possible to use mixtures of chain extenders and crosslinkers.

To adjust the hardness of the PU elastomers, the structural components b), c) and d) can be varied in relatively broad proportions, the hardness increasing with increasing content of component d) in the reaction mixture.

To obtain a desired hardness of the material, the required amounts of the structural components b), c) and d) can be determined experimentally in a simple manner. Advantageously used are 1 to 50 parts by weight, preferably 3 to 20 parts by weight of the chain extender and / or crosslinker d), based on 100 parts by weight of the higher molecular weight compounds b) and c).

As component e), amine catalysts familiar to the person skilled in the art can be used, for example tertiary amines, such as triethylamine, tributylamine, N-methylmorpholine, N-ethylmorpholine, N, N, N ', N'-tetramethylethylenediamine, pentamethyldiethylenethene triamine and higher homologs (DE-A 26 24 527 and 26 24 528), 1,4-diaza-bicyclo [2,2,2] octane, N-methyl-N'-dimethylaminoethyl-piperazine, bis (dimethylaminoalkyl ) -piperazines, N, N-dimethylbenzylamine, N, N-dimethylcyclohexylamine, N, N-diethylbenzylamine, bis (N, N-diethylaminoethyl) adipate, N, N, N ', N'-tetramethyl-1,3-butanediamine , N, N-dimethyl-β-phenylethylamine, bis (dimethylaminopropyl) urea, 1,2-dimethylimidazole, 2-methylimidazole, monocyclic and bicyclic amidines, bis (dialkylamino) alkyl ethers and amide groups (preferably formamide groups ) having tertiary amines according to DE-A 25 23 633 and 27 32 292). Also suitable catalysts are known Mannich bases from secondary amines, such as dimethylamine, and aldehydes, preferably formaldehyde, or ketones, such as acetone, methyl ethyl ketone or cyclohexanone, and phenols, such as phenol, nonylphenol or bisphenol. For example, triethanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N, N-dimethylethanolamine, their reaction products with alkylene oxides such as propylene oxide and / or ethylene oxide and secondary tertiary amines according to DE are compared with isocyanate-active hydrogen atoms -A 27 32 292. Further catalysts which may be used are silaamines having carbon-silicon bonds, as described in US Pat. No. 3,620,984, for example 2,2,4-trimethyl-2-silamorpholine and 1,3- diethyl-aminomethyl-tetramethyl-disiloxane. Furthermore, nitrogen-containing bases such as tetraalkylammonium hydroxides, furthermore hexahydrotriazines come into consideration. The reaction between NCO groups and Zerewitinoff-active hydrogen atoms is also greatly accelerated by lactams and azalactams. According to the invention, it is also possible to use organic metal compounds, in particular organic tin compounds, as additional catalysts. Suitable organometallic, catalytically active compounds, besides tin derivatives, are the sulfur-containing compounds, such as di-n-octyl-tin-mercaptide, preferably tin (II) salts of carboxylic acids, such as tin (II) acetate, tin (II) octoate, tin ( II) -ethylhexoate and tin (II) laurate and tin (IV) compounds, for example dibutyltin oxide, dibutyltin dichloride, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate or dioctyltin diacetate, as well as titanium-containing compounds such as titanium and bismuth alcoholates and carboxylates ,

The catalysts or catalyst combinations are generally used in an amount between about 0.001 and 10 wt .-%, in particular 0.01 to 1 wt .-% based on the total amount of compounds having at least two isocyanate-reactive hydrogen atoms.

In the component f) quaternary alkylammonium monoalkyl sulfates known to those skilled in the art are used, wherein the four alkyl radicals assigned to the ammonium cation independently of one another have a chain length of 1 to 20 carbon atoms and can be linear, branched and partly cyclic and at most a total sum of 70 carbon atoms. The alkyl radical of the sulfate anion may have a chain length of 2 to 5 carbon atoms.

Suitable compounds (i) of component (f2) are, for example, alkyl esters of oxalic acid, malonic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid. For the esterification of dicarboxylic acids, for example, aliphatic and alicyclic monools such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, ethylene hexanol, octanol, decanol and dodecanol and cyclohexanol are suitable, as well as their isomers and aryl alcohols such as phenol and its alkyl-substituted derivatives and naphthol and its alkyl-substituted derivatives.

Suitable compounds (ii) of component (f2) are γ-butyrolactone, γ-valerolactone, α, γ, β, γ and γγ-dimethylbutyrolactone or else mixtures thereof.

In the absence of moisture and physically or chemically acting blowing agents, compact PUR elastomers, for example PUR cast elastomers, can be prepared by the process according to the invention.

For the preparation of cellular, preferably microcellular PUR elastomers is preferably used as blowing agent g) water which reacts with the organic polyisocyanates a) or with isocyanate prepolymers in situ to form carbon dioxide and amino groups, which in turn react with further isocyanate groups to urea groups and hereby act as a chain extender.

If water is added to the polyurethane formulation to adjust the desired density, it is usually used in amounts of from 0.001 to 3.0% by weight, preferably from 0.01 to 2.0% by weight and in particular from 0.05 to 0.8 wt .-%, based on the weight of the structural components a), b) and optionally c) and d) used.

As propellant g) instead of water or preferably in combination with water and gases or volatile inorganic or organic substances which evaporate under the influence of the exothermic polyaddition reaction and preferably has a boiling point under normal pressure in the range of -40 to 120 ° C, preferably from 10 to 90 ° C, are used as physical blowing agents. Suitable organic blowing agents are, for example, acetone, ethyl acetate, halogen-substituted alkanes or perhalogenated alkanes, such as (R134a, R141b, R365mfc, R245fa), butane, pentane, cyclopentane, hexane, cyclohexane, heptane or diethyl ether, as inorganic blowing agents, for example air, CO ₂ or N. ₂ O in question. A blowing effect can also be achieved by adding compounds which decompose at temperatures above room temperature with elimination of gases, for example nitrogen and / or carbon dioxide, such as azo compounds, eg azodicarbonamide or azoisobutyronitrile, or salts, such as ammonium bicarbonate, ammonium carbamate or ammonium salts of organic carboxylic acids , For example, the monoammonium salts of malonic acid, boric acid, formic acid or acetic acid. Further examples of blowing agents as well as details about the use of blowing agents are in R. Vieweg, A. Höchtlen (Hrsg.): "Plastic manual", volume VII, Carl Hanser publishing house, Munich 3rd edition, 1993, p.115- 118, 710-715.

The appropriately used amount of solid propellants, low-boiling liquids or gases, each individually or in the form of mixtures, for. B. can be used as liquid or gas mixtures or as gas-liquid mixtures, depends on the desired density and the amount of water used. The required quantities can be easily determined experimentally. Satisfactory results usually provide amounts of solids of from 0.5 to 35% by weight, preferably from 2 to 15% by weight, liquid amounts of from 0.5 to 30% by weight, preferably from 0.8 to 18% by weight, and / or gas amounts of 0.01 to 80 wt .-%, preferably from 10 to 50 wt .-%, each based on the weight of the structural components a), b), c) and d). The gas loading with z. As air, carbon dioxide, nitrogen and / or helium can be carried out both via the relatively high molecular weight polyhydroxyl compounds b) and c), via the low molecular weight chain extender and / or crosslinking agent d) and via the polyisocyanates a) or via a) and b) and optionally c) and d).

If desired, additives h) can be incorporated into the reaction mixture for the preparation of the compact and cellular PU elastomers. Mention may be made, for example, of surface-active additives, such as emulsifiers, foam stabilizers, cell regulators, flame retardants, nucleating agents, antioxidants, stabilizers, lubricants and mold release agents, dyes, dispersants and pigments. As emulsifiers are e.g. the sodium salts of castor oil sulfonates or salts of fatty acids with amines such as diethylamine or diethanolamine stearic acid. Also, alkali metal or ammonium salts of sulfonic acids such as dodecylbenzenesulfonic acid or dinaphthylmethanedisulfonic acid or of fatty acids such as ricinoleic acid or of polymeric fatty acids can also be used as surface-active additives. Suitable foam stabilizers are in particular polyethersiloxanes, especially water-soluble representatives. These compounds are generally designed so that a copolymer of ethylene oxide and propylene oxide is connected to a Polydimethylsiloxanrest. Such foam stabilizers are e.g. in US-A 2,834,748, 2,917,480 and 3,629,308. Of particular interest are often allophanate branched polysiloxane-polyoxyalkylene copolymers according to DE-A 25 58 523. Also suitable are other organopolysiloxanes, oxyethylated alkylphenols, oxyethylated fatty alcohols, paraffin oils, castor oil or Ricinolsäureester, Turkish red oil, peanut oil and cell regulators such as paraffins, fatty alcohols and polydimethylsiloxanes. Oligomeric polyacrylates having polyoxyalkylene and fluoroalkane radicals as side groups are also suitable for improving the emulsifying action, the dispersion of the filler, the cell structure and / or for stabilizing it. The surface-active substances are usually used in amounts of from 0.01 to 5 parts by weight, based on 100 parts by weight of the higher molecular weight polyhydroxyl compounds b) and c). It is also possible to add reaction retardants, furthermore pigments or dyes and flame retardants known per se, furthermore stabilizers against aging and weathering, plasticizers and fungistatic and bacteriostatic substances.

Further examples of optionally used according to the invention surface-active additives and foam stabilizers and cell regulators, reaction retarders, stabilizers, flame retardants, plasticizers, dyes and fillers and fungistatic and bacteriostatic substances and details on the use and mode of action of these additives are in R. Vieweg, A. Höchtlen ( Eds.): "Kunststoff-Handbuch", Volume VII, Carl-Hanser-Verlag, Munich, 3rd edition, 1993, p.118-124 described.

The PUR materials of the present invention can be prepared by the methods described in the literature, e.g. the one-shot or prepolymer process, with the help of known in the art in principle mixing devices. Preferably, they are produced by the prepolymer method.

In one embodiment of the preparation of the PUR materials according to the invention, the starting components in the absence of blowing agents g) usually mixed homogeneously at a temperature of 20 to 80 ° C, preferably from 25 to 60 ° C, the reaction mixture introduced into an open, optionally tempered mold and allowed to cure. In a further variant of the preparation of the PU elastomers according to the invention, the synthesis components are mixed in the same manner in the presence of blowing agents g), preferably water, and introduced into the optionally tempered mold. After filling, the mold is closed and the reaction mixture is left under compression, e.g. with a degree of compaction (ratio of molding density to free foam density) of 1.05 to 8, preferably from 1.1 to 6 and in particular from 1.2 to 4 to form moldings. Once the moldings have sufficient strength, they are removed from the mold. The demolding times are u.a. depending on the temperature and the geometry of the mold and the reactivity of the reaction mixture and are usually 2 to 15 minutes.

Compact PUR elastomers according to the invention have, inter alia, depending on the filler content and type, a density of 0.8 to 1.4 g / cm ³ , preferably 0.9 to 1.20 g / cm ³ . Cellular PUR elastomers of the invention exhibit densities of from 0.2 to 1.4 g / cm ³ , preferably from 0.25 to 0.75 g / cm ³ .

Such polyurethane plastics are particularly valuable raw materials for the production of antistatic footwear, in particular for shoe soles according to EN 344 in single or multi-layer construction and shoe components as well as rollers, spring elements, mold-foamed mats and upholstery and safety components in the automotive industry.

Examples

The preparation of the polyurethane test specimens was carried out such that the A component at 45 ° C in a low pressure foaming unit (NDI) with the B component at 45 ° C at a mass ratio (MV) of A component to B component as mixed in the examples, the mixture poured into an aluminum mold tempered to 50 ° C, closed the mold and demolded the elastomer after 3 minutes.

On the thus prepared elastomeric plates (density 550 kg / m ³ ), the electrostatic discharge resistance was measured after each specified storage period. The measuring arrangement corresponded to that described in EN 344, chapter 5.7. Test climate was 20 ° C and 55% humidity.

Used materials polyester polyol:

Ethanediol-diethylene glycol polyadipate (ratio 14.3: 24.4: 61.3) having a number average molecular weight of 2000 g / mol

Dabco / EG: amine catalyst diaza-bicyclo [2.2.2] octane in ethylene glycol (weight ratio 1: 2)

Antistatic A:

80% solution of trimethyl dodecyl ammonium ethyl sulfate in ethanediol

Surfactant DC 193: Silicone stabilizer Dabco DC193 from Air Products

Component B:

56 Gew-%

4,4'-MDI

6 Gew-%

polymeres MDI (29,8 Gew-% NCO, Funktionalität 2,1)

38 Gew-%

Ethandiol-Diethylenglykol-Polyadipat (Verhältnis 14,3 : 24,4 : 61,3) mit einer zahlenmittleren Molmasse von 2000 g/mol

Prepolymer having an NCO content of 19% obtained by reacting:

56% by weight

4,4'-MDI

6% by weight

polymeric MDI (29.8% by weight NCO, functionality 2.1)

38% by weight

Ethanediol-diethylene glycol polyadipate (ratio 14.3: 24.4: 61.3) having a number average molecular weight of 2000 g / mol

The foaming results and results of the resistance measurement are given in Table 1.

The numerical values in the table are% by weight, unless otherwise specified.

The smaller the measured values of the volume resistance, the better the antistatic effect.

In Examples 2 and 3, 5 and 6, and 8 and 9, the increased effectiveness (i.e., lower antistatic) over the respective Comparative Examples 1, 4, and 7 is clearly seen.

Claims (3)

Polyurethane elastomers obtainable by reaction of a) di- and / or polyisocyanates with b) at least one polyester polyol having an OH number of from 20 to 280, preferably from 28 to 150, and an average functionality of from 1.5 to 3, preferably from 1.8 to 2.4, c) optionally further polyether polyols having OH numbers of 10 to 150 and functionalities of 1.5 to 8.0, preferably 1.8 to 6.0 and / or Polyetheresterpolyolen having OH numbers of 20 to 280 and functionalities of 1.5 to 3.0, preferably 1.8 to 2.4, d) optionally low molecular weight chain extenders and / or crosslinkers having OH numbers from 150 to 1870,
in the presence of e) amine and / or organometallic catalysts, f) Antistatic agents consisting of f1) quaternary alkylammonium monoalkyl sulfates

R ¹ R ² R ³ R ⁴ N ⁺ R ⁵ SO ₄ ^-

wherein R ¹ , R ² , R ³ and R ⁴ independently of one another are alkyl radicals having 1 to 20 carbon atoms, the total number of carbon atoms of the four radicals not exceeding 70,
and R ^{5 is} an alkyl radical having 2 to 10 carbon atoms,
and f2) compounds from the group consisting of (i) linear, OH group-free dicarboxylic acid esters

wherein X is a radical having 1 to 20 carbon atoms or is a bond and R ⁶ and R ^{7 are} independently alkyl radicals having 1 to 20 carbon atoms, (ii) lactones selected from the group consisting of γ-butyrolactone, γ-valerolactone, α, γ-, β, γ- and γγ-dimethylbutyrolactone and (iii) mixtures of (i) and (ii), g) optionally propellants and h) optionally additives and / or auxiliaries,
wherein the quaternary alkyl ammonium alkyl sulfates f1) in an amount of 0.5 to 15 wt .-%, based on the polyurethane elastomer, and the compounds f2) in an amount of 1.5 to 7.5 wt .-%. Shaped body containing polyurethane elastomers according to claim 1. Use of the polyurethane elastomers according to claim 1 for the production of rolls, spring elements, mold-foamed mats and upholstery, safety components in the automotive industry, shoe soles and shoe components.